Impact of hydrogen SAE J2601 fueling methods on fueling time of light-duty fuel cell electric vehicles

Hydrogen fuel cell electric vehicles (HFCEVs) are zero-emission vehicles (ZEVs) that can provide drivers a similar experience to conventional internal combustion engine vehicles (ICEVs), in terms of fueling time and performance (i.e. power and driving range). The Society of Automotive Engineers (SAE) developed fueling protocol J2601 for light-duty HFCEVs to ensure safe vehicle fills while maximizing fueling performance. This study employs a physical model that simulates and compares the fueling performance of two fueling methods, known as the “lookup table” method and the “MC formula” method, within the SAE J2601 protocol. Both the fueling methods provide fast fueling of HFCEVs within minutes, but the MC formula method takes advantage of active measurement of precooling temperature to dynamically control the fueling process, and thereby provides faster vehicle fills. The MC formula method greatly reduces fueling time compared to the lookup table method at higher ambient temperatures, as well as when the precooling temperature falls on the colder side of the expected temperature window for all station types. Although the SAE J2601 lookup table method is the currently implemented standard for refueling hydrogen fuel cell vehicles, the MC formula method provides significant fueling time advantages in certain conditions; these warrant its implementation in future hydrogen refueling stations for better customer satisfaction with fueling experience of HFCEVs.     

Optimization of hydrogen vehicle refueling via dynamic simulation

A dynamic model has been developed to analyze and optimize the thermodynamics and design of hydrogen refueling stations. The model is based on Dymola software and incorporates discrete components. Two refueling station designs were simulated and compared. The modeling results indicate that pressure loss in the vehicle's storage system is one of the main factors determining the mass flow and peak cooling requirements of the refueling process. The design of the refueling station does not influence the refueling of the vehicle when the requirements of the technical information report J2601 from Society of Automotive Engineers are met. However, by using multiple pressure stages in the tanks at the refueling station (instead of a single high-pressure tank), the total energy demand for cooling can be reduced by 12%, and the compressor power consumption can be reduced by 17%. The time between refueling is reduced by 5%, and the total amount of stored hydrogen at high pressure is reduced by 20%.     

Risk-constrained design of autonomous hybrid refueling station for hydrogen and electric vehicles using information gap decision theory

The proposed autonomous hybrid charging station in this paper is energized by a photovoltaic (PV) system, which should provide electric vehicles (EVs), and water electrolyzer (WE) with electricity. The WE operates by using electricity to produce and store hydrogen to feed hydrogen vehicles (HVs). Moreover, a fuel cell (FC) is allocated to the system, which uses the stored hydrogen to regenerate electricity the PV system is beyond reach. A supplementary diesel generator is also installed in the charging station to avoid power shortage as a conservative measurement. The hydrogen and electric demand of the station is accompanied by uncertainties, which should be taken into account in designing the charging station. Therefore, information-gap decision theory (IGDT) is employed to deal with the uncertainties. This approach provides the investor with three different strategies of risk-averse strategy (RAS), risk-neutral strategy (RNS), and risk-seeker strategy (RSS), which can help the investor with making a better decision. The outcome of the simulation proved that in RAS if the investor decides to invest 13.9% more capital, based on the robustness function, the charging station withstands the 9.6% deviation of uncertain parameters’ fraction error. However, should the investor decide to take risks in the construction of the charging station, by paying 13.9% less, the system is 10.7% fragile to the information-gap of uncertainties. Besides, the rated power of the PV system reaches from 1612 kW in RNS to 1731 kW in RAS while it decreased to 1479 kW in RSS.     

Manufacturing competitiveness analysis for hydrogen refueling stations

Fuel cell electric vehicles (FCEVs) have now entered the market as zero-emission vehicles. Original equipment manufacturers such as Toyota, Honda, and Hyundai have released commercial cars in parallel with efforts focusing on the development of hydrogen refueling infrastructure to support new FCEV fleets. Persistent challenges for FCEVs include high initial vehicle cost and the availability of hydrogen stations to support FCEV fleets. This study sheds light on the factors that drive manufacturing competitiveness of the principal systems in hydrogen refueling stations, including compressors, storage tanks, precoolers, and dispensers. To explore major cost drivers and investigate possible cost reduction areas, bottom-up manufacturing cost models were developed for these systems. Results from these manufacturing cost models show there is substantial room for cost reductions through economies of scale, as fixed costs can be spread over more units. Results also show that purchasing larger quantities of commodity and purchased parts can drive significant cost reductions. Intuitively, these cost reductions will be reflected in lower hydrogen fuel prices. A simple cost analysis shows there is some room for cost reduction in the manufacturing cost of the hydrogen refueling station systems, which could reach 35% or more when achieving production rates of more than 100 units per year. We estimated the potential cost reduction in hydrogen compression, storage and dispensing as a result of capital cost reduction to reach 5% or more when hydrogen refueling station systems are produced at scale.     

Liquid pump-enabled hydrogen refueling system for heavy duty fuel cell vehicles: Pump performance and J2601-compliant fills with precooling

We have developed a hydrogen (H₂) refueling solution capable of delivering precooled, compressed gaseous hydrogen for heavy duty vehicle (HDV) refueling applications. The system uses a submerged pump to deliver pressurized liquid H₂ from a cryogenic storage tank to a dispensing control loop that vaporizes the liquid and adjusts the pressure and temperature of the resulting gas to enable refueling at 35 MPa and temperatures as low as ?40 °C. A full-scale mobile refueler was fabricated and tested over a 6-month campaign to validate its performance. We report results from tests involving a total of 9000 kg of liquid H₂ pumped and 1350 filling cycles over a range of conditions. Notably, the system was able to repeatably complete multiple, back-to-back 30 kg filling cycles in under 6 min each, in full compliance with the SAE J2601-2 standard, demonstrating its potential for rapid-throughput HDV refueling applications.     

Overall efficiency comparison between the fueling methods of SAEJ2601 using dynamic simulations

This study concerns MC Formula and the table-based protocol hydrogen fueling methods described in SAE J2601 2016 edition fueling protocols for light duty gaseous hydrogen surface vehicles. It considers the overall efficiency and performance of the two methods. This is achieved by dynamic simulations, using the Dymola hydrogen fueling station library. The MC formula and table-based methods are implemented in the library and different simulations are performed, to evaluate the performance of the two different fueling methods under various conditions. The efficiency is evaluated according to; fueling time, State of Charge levels and total energy consumption. The MC formula is up to 26% faster. The state of charge levels are similar between the table-based and MC formula. The energy consumption for the MC formula is up to 6.9% higher than for the table-based method. Comparing consecutive fuelings without recharging the station, the table-based method is able to fill 7 vehicles and the MC formula 5 vehicles.     

Off-grid solar powered charging station for electric and hydrogen vehicles including fuel cell and hydrogen storage

This paper designs an off-grid charging station for electric and hydrogen vehicles. Both the electric and hydrogen vehicles are charged at the same time. They appear as two electrical and hydrogen load demand on the charging station and the charging station is powered by solar panels. The output power of solar system is separated into two parts. On part of solar power is used to supply the electrical load demand (to charge the electric vehicles) and rest runs water electrolyzer and it will be converted to the hydrogen. The hydrogen is stored and it supplies the hydrogen load demand (to charge the hydrogen-burning vehicles). The uncertainty of parameters (solar energy, consumed power by electrical vehicles, and consumed power by hydrogen vehicles) is included and modeled. The fuel cell is added to the charging station to deal with such uncertainty. The fuel cell runs on hydrogen and produces electrical energy to supply electrical loading under uncertainties. The diesel generator is also added to the charging station as a supplementary generation. The problem is modeled as stochastic optimization programming and minimizes the investment and operational costs of solar and diesel systems. The introduced planning finds optimal rated powers of solar system and diesel generator, operation pattern for diesel generator and fuel cell, and the stored hydrogen. The results confirm that the cost of changing station is covered by investment cost of solar system (95%), operational cost of diesel generator (4.5%), and investment cost of diesel generator (0.5%). The fuel cell and diesel generator supply the load demand when the solar energy is zero. About 97% of solar energy will be converted to hydrogen and stored. The optimal operation of diesel generator reduces the cost approximately 15%.     

Effect of cascade storage system topology on the cooling energy consumption in fueling stations for hydrogen vehicles

One of the main obstacles of the diffusion of fuel cell electric vehicles (FCEV) is the refueling system. The new stations follow the refueling protocol from the Society of Automotive Engineers where the way to reach the target pressure is not explained. This work analyzes the thermodynamics of a hydrogen fueling station in order to study the effects of the cascade storage system topology on the energy consumption for the cooling facility. It is found that the energy consumption for cooling increases, expanding the total volume of the cascade storage system. Comparing the optimal and the worst volume configurations of the cascade storage tanks at different ambient temperatures, the energy saving is approximately 12% when the average ambient temperature is 20 °C and around 20% when the average ambient temperature is 30 °C. The energy consumption for cooling is significantly influenced by the topology of the cascade storage system and it is particularly relevant in the case of low daily-dispensed amount of hydrogen.     

Behavioral response to hydrogen fuel cell vehicles and refueling: Results of California drive clinics

Over the last several decades, hydrogen fuel cell vehicles (FCVs) have emerged as a zero tailpipe-emission alternative to the battery electric vehicle (EV). To address questions about consumer reaction to FCVs, this report presents the results of a “ride-and-drive” clinic series (N = 182) held in 2007 with a Mercedes-Benz A-Class “F-Cell” hydrogen FCV. The clinic evaluated participant reactions to driving and riding in an FCV, as well as vehicle refueling. Pre-and post-clinic surveys assessed consumer response. More than 80% left with a positive overall impression of hydrogen. The majority expressed a willingness to travel 5–10 min to find a hydrogen station. More than 90% of participants would consider an FCV driving range of 300 miles (480 km) to be acceptable. Stated willingness-to-pay preferences were explored. The results show that short-term exposure can improve consumer perceptions of hydrogen performance and safety among people who are the more likely early adopters.     

Liquid pump-enabled hydrogen refueling system for heavy duty fuel cell vehicles: Fuel cell bus refueling demonstration at Stark Area Regional Transit Authority (SARTA)

We have demonstrated a hydrogen (H₂) refueling solution capable of delivering precooled, compressed gaseous hydrogen for heavy duty vehicle (HDV) refueling applications by refueling transit buses over a three-month period under real-world conditions. The system uses a submerged pump to deliver pressurized liquid H₂ from a cryogenic storage tank to a dispensing control loop that vaporizes the liquid and adjusts the pressure and temperature of the resulting gas to enable refueling at 35 MPa and temperatures as low as −40 °C, consistent with the SAE J2601 standard. Using our full-scale mobile refueler, we completed 118 individual bus filling events using 13 different vehicles, involving a total of 3,700 kg of H₂ dispensed. We report filling statistics from the entire campaign, details on individual fills (including fill times, final state of charge, benefits of pre-cooled fills, and back-to-back filling capabilities), and discuss transit agency feedback on technology performance. In our final test, the system successfully completed an endurance test using a single dispenser involving 52 consecutive individual fills over an 11.5-h period, dispensing 1,322 kg of H₂ with an average fill rate of 3.4 kg/min and peak rate of 7.1 kg/min, and reaching an average SOC of 97.6% across all fills.     

Near-term location planning of hydrogen refueling stations in Yokohama City

Establishing hydrogen refueling stations is key to transition into a hydrogen economy. To achieve this, a near-term, city-level roll-out plan is required, as Japan is shifting from the demonstration to implementation stage of a hydrogen economy. The aim of this study was to devise a plan to identify near-term locations to build hydrogen refueling stations in Yokohama City, Japan. Our plan provides information on the potential location of hydrogen refueling stations for 2020–2030. We considered mobile and parallel-siting type refueling stations; the locations of these stations were determined by matching the supply and demand estimated from hybrid vehicle ownership data and the available space in existing gas stations based on a safety perspective. The results reaffirmed the importance of planning the locations of hydrogen refueling stations and highlighted the suitability of using mobile-type stations. This was based on the uncertainty in fuel demand for fuel cell vehicles during the implementation stage of the hydrogen economy.     

Performance of a hydrogen refueling station in the early years of commercial fuel cell vehicle deployment

Since 2003, the National Fuel Cell Research Center at the University of California, Irvine (UCI) has operated the first U.S. publicly accessible hydrogen refueling station (HRS). During this period, the UCI HRS supported all manufacturers in the early, pre-commercialization years of the fuel cell electric vehicle (FCEV). This paper describes and analyzes the performance of the UCI HRS during the first five years of FCEV commercialization, over which time the station has dispensed the most hydrogen daily in the California network. The station performance is compared to aggregate data published by NREL for all U.S. HRSs. Using the Hydrogen Delivery Scenario Analysis Model, typical daily refueling profiles are analyzed to determine the effect on HRS design. The results show different daily refueling profiles could substantially affect HRS design and ultimately the cost of hydrogen. While technical issues have been reduced, the compressor, dispenser, and fueling rate are areas for improvement.     

Dynamic competition between plug-in hybrid and hydrogen fuel cell vehicles for personal transportation

This article addresses the issue of the diffusion of hydrogen cars in the market, particularly the competition with electric cars for the replacement of conventional vehicles. Using the multi-technological competition model developed by Le Bas and Baron-Sylvester’s (Diffusion technologique non binaire et schéma épidémiologique. Une reconsidération. Economie Appliquée 1995; tome XLVIII(3):71–101), it is shown that the early deployment of plug-in hybrid vehicles—the only electric technology which can compete with fuel cell cars in the multipurpose vehicle field—risks closing the market for hydrogen in the future. Moreover, the advent of the hydrogen vehicle depends on the rapid advancements in fuel cell technologies, as well as on the existence of an infrastructure with a sufficient coverage.     

Comments on solid state hydrogen storage systems design for fuel cell vehicles

In recent years, significant research and development efforts were spent on hydrogen storage technologies with the goal of realizing a breakthrough for fuel cell vehicle applications. This article scrutinizes design targets and material screening criteria for solid state hydrogen storage. Adopting an automotive engineering point of view, four important, but often neglected, issues are discussed: 1) volumetric storage capacity, 2) heat transfer for desorption, 3) recharging at low temperatures and 4) cold start of the vehicle. The article shall help to understand the requirements and support the research community when screening new materials.     

Development of emergency response strategies for typical accidents of hydrogen fuel cell electric vehicles

First responders are facing new challenges in handling hydrogen vehicle accidents. Hazard analyses, physical effects evaluations, and accident progression studies are performed to develop appropriate emergency response strategies. Results show that hydrogen release from thermally-activated pressure relief device and catastrophic tank rupture are the two major accidents leading to large hazard zones. Three types of hazard distances and accident durations are determined by the novel nomograms built in the paper. The nomograms indicate that fireball radiation leads to longer hazard distances than overpressure effects in the event of catastrophic tank rupture. Based on the hydrogen physical effects evaluations and accident progression analyses, new emergency response strategies are developed to deal with the typical accidents of hydrogen vehicles, including traffic collision on a road, vehicle fire in a parking lot, and hydrogen leak during refueling at a station. Rapid initial assessment techniques, firefighting strategy, rescue operation tactics and waste disposal pre-treatment are proposed.     

Design tool for estimating metal hydride storage system characteristics for light-duty hydrogen fuel cell vehicles

The U.S. Department of Energy (DOE) has developed the Framework model to simulate fuel cell-based light-duty vehicle operation for various hydrogen storage systems. This transient model simulates the performance of the storage system, fuel cell, and vehicle for comparison to DOE's Technical Targets using four drive cycles. Metal hydride hydrogen storage models have been developed for the Framework model. Despite the utility of this model, it requires that material researchers input system design specifications that cannot be easily estimated. To address this challenge, a design tool has been developed that allows researchers to directly enter physical and thermodynamic metal hydride properties into a simple sizing module that then estimates the systems parameters required to run the storage system model. This design tool can also be used as a standalone MS Excel model to estimate the storage system mass and volume outside of Framework and compare it to the DOE Technical Targets. This model will be explained and exercised with existing hydrogen storage materials.     

Single-tank storage versus multi-tank cascade system in hydrogen refueling stations for fuel cell buses

Many countries in Europe are investing in fuel cell bus technology with the expected mobilization of more than 1200 buses across Europe in the following years. The scaling-up will make indispensable a more effective design and management of hydrogen refueling stations to improve the refueling phase in terms of refueling time and dispensed quantity while containing the investment and operation costs. In the present study, a previously developed dynamic lumped model of a hydrogen refueling process, developed in MATLAB, is used to analyze tank-to-tank fuel cell buses (30–40 kg_H2 at 350 bar) refueling operations comparing a single-tank storage with a multi-tank cascade system. The new-built Aalborg (DK) hydrogen refueling station serves as a case study for the cascade design. In general, a cascading refueling approach from multiple storage tanks at different pressure levels provides the opportunity for a more optimized management of the station storage, reducing the pressure differential between the refueling and refueled tanks throughout the whole refueling process, thus reducing compression energy. This study demonstrates the validity of these aspects for heavy-duty applications through the technical evaluation of the refueling time, gas heating, compression energy consumption and hydrogen utilization, filling the literature gap on cascade versus single tank refueling comparison. Furthermore, a simplified calculation of the capital and operating expenditures is conducted, denoting the cost-effectiveness of the cascade configuration under study. Finally, the effect of different pressure switching points between the storage tanks is investigated, showing that a lower medium pressure usage reduces the compression energy consumption and increases the station flexibility.     

Hydrogen monitoring requirements in the global technical regulation on hydrogen and fuel cell vehicles

The United Nations Economic Commission for Europe Global Technical Regulation (GTR) Number 13 (Global Technical Regulation on Hydrogen and Fuel Cell Vehicles) is the defining document regulating safety requirements in hydrogen vehicles, and in particular, fuel cell electric vehicles (FCEVs). GTR Number 13 has been formally adopted and will serve as the basis for the national regulatory standards for FCEV safety in North America (led by the United States), Japan, Korea, and the European Union. The GTR defines safety requirements for these vehicles, including specifications on the allowable hydrogen levels in vehicle enclosures during in-use and post-crash conditions and on the allowable hydrogen emissions levels in vehicle exhaust during certain modes of normal operation. However, in order to be incorporated into national regulations, that is, to be legally binding, methods to verify compliance with the specific requirements must exist. In a collaborative program, the Sensor Laboratories at the National Renewable Energy Laboratory in the United States and the Joint Research Centre, Institute for Energy and Transport in the Netherlands have been evaluating and developing analytical methods that can be used to verify compliance with the hydrogen release requirements as specified in the GTR.     

Public perception on hydrogen infrastructure in Japan: Influence of rollout of commercial fuel cell vehicles

A public survey was conducted in March 2015 in Japan asking public awareness, knowledge, perception and acceptance regarding hydrogen, hydrogen infrastructure and fuel cell vehicle. Changes in answers were found by comparing results of current survey to those of the two previous surveys that were conducted six and seven years ago. We found a large increase in the awareness and relatively a small improvement on knowledge on hydrogen energy, hydrogen infrastructure and fuel cell vehicle from the previous surveys. In contrast we did not find much changes in perception of risk and benefit on hydrogen society and hydrogen station and public acceptance of hydrogen infrastructure. Through the regression analyses we found the small influence of time background as well as the influence of risk and benefit perception of hydrogen infrastructure on the acceptance. In conclusion, we find people have become a little more positive about hydrogen infrastructure in the baseline but more cautious about the risk and benefits. This can be interpreted as a change in the quality of perception and acceptance, that is, the favorable prejudice to hydrogen energy and fuel cell technologies has changed towards a slightly more rational support.     

A techno-economic analysis of decentralized electrolytic hydrogen production for fuel cell vehicles

Hydrogen from decentralized water electrolysis is one of the main fuelling options considered for future fuel cell vehicles. In this study, a model is developed to determine the key technical and economic parameters influencing the competitive position of decentralized electrolytic hydrogen. This model incorporates the capital, maintenance and energy costs of water electrolysis, as well as a monetary valuation of the associated greenhouse gas (GHG) emissions. It is used to analyze the competitive position of electrolytic hydrogen in three specific locations with distinct electricity mix: Vancouver, Los Angeles and Paris. Using local electricity prices and fuel taxes, electrolytic hydrogen is found to be commercially viable in Vancouver and Paris. Hydrogen storage comes out as the most important technical issue. But more than any technical issue, electricity prices and fuel taxes emerge as the two dominant issues affecting the competitive position of electrolytic hydrogen. The monetary valuation of GHG emissions, based on a price of $20/ton of CO₂, is found to be generally insufficient to tilt the balance in favor of electrolytic hydrogen.